Closure operator



April 4, 1961 Filed Oct. 17, 1955 7' Sheets-Sheet 1 5 N K) "I k I INVEN TOR. finRozoLJ'Tm/E/vm)\ ATroRA/Em April 4, 1961 H. L. STAVENAU 2,977,810

CLOSURE OPERATOR Filed Oct. 17, 1955 v Sheets-Sheet 2 or F9 SER v/cnve \QOSITION SCREEN IN VEN TOR. fiARoLoLJTm E/v/w ATTORNE Yo- April 4, 1961 H. L. STAVENAU CLOSURE OPERATOR 7 Sheets-Sheet 3 Filed Oct. 17, 1 955 INVENTOR. flARowLJml/fivnu WWWW D TORNEY:

April 4, 1961 H. L. STAVENAU 2,977,810

CLOSURE OPERATOR Filed Oct. 17, 1955 7 Sheets-Sheet 4 IN VEN TOR. fiARaL 0L 3m vE/vnu ATTORNEYS April 4, 19 1 H. L. STAVENAU 2,977,810

CLOSURE OPERATOR Filed Oct. 1'7, 1955 7 Sheets-Sheet 5 26R BUTTdM TIER-D lid/001E TIER C TOP TIER 5 I N V EN TOR. #42040 A .J'm VEN/IU ATTORNEY:-

April 4, 1961 H. L.- STAVENAU 2,977,810 CLOSURE OPERATOR Filed Oct. 17, 1955 7 SheetsSheet a ATTORNE'YJ April 4, 1961 H. L. STAVENAU 2,977,810

CLOSURE OPERATOR Filed Oct. 17, 1955 7 Sheets-Sheet 7 IN V EN TOR. /7'AROLDL$TA VENAU ATTORNEYJ 4 WW /z.

2,977,810 CLOSURE OPERATOR Harold L. Stavenau, Manlrato, Minn., assignor to Truth Tool Company, Mankato, Minm, a corporation of Minnesota Filed Oct. 17, 1955, Ser. No. 540,671

4 Claims. (Cl. 74- 96) This invention relates to improved closure operators and more especially to manual operators foropening and closing windows, doors, hatchway closures and the like, where the primary purpose of the opening is ventilation rather than access. A principal field of usefulness of the invention is as a window operator for canopy, and outwardly opening casement windows of dwelling houses. Window operators heretofore in common use for such purposes have been in two main classes, i.e., the slide bar type and the crank type. Each is subject to many disadvantages. The slide-bar type, while economical to make, has had the disadvantage of unsightliness, .undue projection into the building during partial opening and lack of adjustability, or alternatively, cumbersome mode of adjustment. The crank types, while being more attractive in appearance, have the. disadvantage of high cost and lack of strength and, in addition, poor adaptability to the modern canopy-type windows.

It is an object of the present invention to provide an improved closure operator mechanism free from the aforesaid objections of the prior commonly used devices, and in addition to provide strong and durable mechanisms which can be manufactured at low cost for operating canopy windows, outwardly opening casement windows and the like.

It is a further object of the invention to provide an improved but inexpensive window operator for canopy and casement windows.

It is another object of the invention to provide a closure operator of great strength and holding ability, capable of securely holding the window'when in the closed position, yet capable of being detachedly manipulated to allow extreme positioning of the window for cleaning, servicing, application or detachment of storm windows, and the like.

It is a further object of the invention to provide a closure operator of simple construction, durably made and capable of long life, and in which such parts as are necessarily exposed are of functional simplicity and comely appearance.

Other objects of the invention are those inherent in the apparatus herein illustrated, described and claimed.

The present invention is an improvement on the Closure Operator specified and claimed in application Serial No. 520,555, now Patent No. 2,775,446, issued December 25, 1956, filed July 7, 1955.

To the accomplishment of the foregoing and related ends, this invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed. v

The invention is illustrated with reference to the drawings wherein: v

Figure 1 is an elevational view illustrating a modern canopy-type window, shown from the inside and opened, and having the improved closure operator of the present invention attached thereto;

ates Patent f Pfiatented Apr. 4, 1961.

Figure 2 is a vertical sectional view of the window and operator of the present invention illustrating the window in normal open position in solid lines, in a closed position in the generally vertical dotted line, and in a servicing position in a generally horizontal. dotted line, said view being taken along the line in the direction of the arrows of 22 of Figure l execpt that the handle of the operator is sectioned at the line 2'.

Figure 3 is a generally horizontal sectional view of the window and operator taken along the line and looking in the direction 3--3 of Figure 2; a H Figure 4 is an enlarged plan view, partiallybroken away and partially sectioned, of the window operator on a Window, such as shown in Figures 1 to 3, said operator being shown in a window closed,position;

Figure '5 is a vertical sectional view taken along the line and in the direction of the arrows 55 of Figure 4;

Figure 6 is a vertical sectional view taken along the line in the direction of the arrows 6-6 of Figure 5 to illustrate the connection of the window operator actuator arm to the window frame;

Figure 7 is a plan view, part in section, of the end of the actuator arm joined with the cylindrical slide;

Figure 8 is a plan view, partly broken away and partly in section, of the window operator mounted on the frame and illustrating said operator in a normal window pull open position;

Figure 9 is a vertical sectional view taken along the line and in the directions of the arrows 99 of Figure 8 to illustrate the relative positions of the window operator mechanism in a window open position.

Figure 10 is a horizontal sectional view up to a typical casement window in a full opened position to illustrate the single arm actuator modified embodiment of this invention, said view showing a slide hinge form for mounting said casement window;

Figure 11 is a horizontal sectional view to a casement window as illustrated in Figure 10 except that a projected slide hinge form of a hinge mounting is illustrated.

Figure 12 is a plan view, partly broken away and a 7 section of the single arm casement window operator illustrated in Figure 10;

Figure 13 is a vertical sectional view being taken along the line and in the direction of the arrow 13-43 of Figure 12 to further illustrate the single arm casement window operator.

Throughout the drawings, corresponding numerals refer to corresponding parts.

Referring to the drawings, Figures 13 illustratea typical modern canopy window generally designated 10 which is made and sold, mounted in its frame, generally designated 11. The window is attached to the window frame at the upper side portions of the window (indicated at 12) by means of a sliding connection, not illustrated, of which there are several forms in use. The

slidable connection in effect provides a vertical track or groove vertically along the upper side portions of the window frame and the window is provided with a cooperating pin or other device 13 which not only slides vertically but is also free to journal a track (not illustrated) in each side of the window frame 11. By this means the top window member 12 is permitted to move from the dotted line position of Figure 2, downward to any desired position within the limits provided. The window 10 is stabilized and braced by radius rods 1414 at each side of the window. The radius rods serve to provide a pivotal path of motion for the pivot points 15l5 at opposite sides of the window and hence as the topportion of the window moves downwardly, the plane of the window is swung out.

The usual degreeof movements are shown in Figure 2.

These include the closed position, shown in dotted lines and any degree of opening movement to and including the normal full open position shown in full lines. This range of movement is what is accommodated by the window operating mechanism during'normal movement. However, the window may be detached from the windowoperating mechanism and ,be moved further to the servicing position shown in dot-dash lines, in Figure 2, for window washing, servicing storm'windows, etc. It is noted parenthetically that the storm sash, in this design, is a thin metal edged sash and is mounted against the outer face of the window as denoted at SS in Figure 2. The details of canopy window construction vary somewhat but the general configuration and the motions are approximately as here illustrated. The details of the window construction do not, per se, form a part of the present invention except as they may be necessarily included in the novel combinations claimed.

One representative form of my closure operator mechanism of the present invention is shown applied to the window and frame of Figures l-3. In general the mechanism comprises a frame assembly, generally designated 20 on which a crank drum 21 is mounted for rotation on pivot 22. The crank drum is rotated by a lever arm 23 having handle 24 thereon. On the frame assembly there are two pivots 25L and 25R upon which the lever arms generally designated 26L and 26R are adapted to swing. Within the frame assembly 20 there are provided mechanical linkages (which will be described) by means of which the arms 26L and 26R are swung simultaneously toward or away from each other by swinging the cranklever handle assembly 212324. The lever arms 26L and 26R are herein illustrated as of the type which swing as unit about their principal pivots (25L for arm 26L and 25R for arm 26R) and the connection to the window frame is accomplished by a novel slide arrangement, which is a feature of this invention. However, it will be understood that the levers 25L and 25R may, if desired be of the so-called scissors type, hinged intermediate their ends and principal pivots (25L and R) and attachment made to the window frame all as shown in application Ser. No. 520,555, previously referred to, the disclosure thereof being incorporated herein by reference. fore be understood, that in its broader aspects, the present invention may utilize as the mechanical linkage between the operation 20 and the window sash, either the solidtype arm or arms herein illustrated at 26L and 26R, in Figures 1-3 with a slide connection of any appropriate type between the end of each arm and the window frame-or there may be utilized the scissors-type arms illustrated in application Ser. No. 520,555.

Referring to Figures 4-9 particularly, the window operator mechanism generally designated 20 comprises a mounting plate 28 which has a horizontal planar area 28A and a vertically extending flange 28B. The area 28A has a shape which is generally of suflicient area to underly the whole area of or most of the area of the operator mechanism. As shown here, the portion 28A runs from front point 30, to corner 31, thence outward to corner 32, thence backward (toward the window) to curved corner 33 which blends into the rear edge line '34, which as shown in Figure is aligned with the inner seat ing face 11B of the lower member 11A of frame 11. The operator frame piece is symmetrical about the centerline (line 5--5 of Figure 4), and from rear edge line 34 it continues around curved corner 35 to corner 36, thence to corner 37 and to left front point 38. It will be noted that the front flange 28B is the same width as the dimension between corners 32 and 36.

The mounting plate is fashioned to receive wood screws 39, of which four are shown. As many wood screws are used as the service requires and the heads are countersunk so that, when screwed down, the upper surface of area 28A is smooth and unobstructed. In addition plate area 28A is tapped to receive the ends of machine screws T "287mm r P I 40R and 40L which pass through the bores of the tubular pivot pins 25R and 25L of the arms 26R and 26L respectively. Thus as shown in Figure 9, the pivot 25R is tubular and has turned-down ends which seat in apertures of the frame plates and thus space them apart vertically. Then the machine screw 40R passes right down through the bore of pivot 25R and threads into the portion 28A of the mounting plate. The pivot 25L is similar, there being a hold-down machine screw 40L through its bore for fastening purposes.

The operator mechanism is made up like a sandwich and is composed of five vertical layers which for convenience are designated, from top to bottom, by the fol- It will therelowing legends Top Plate A, Top Tier B, Middle Tier C, Bottom Tier D and Bottom Plate E. The top and bottom plates A and E are preferably identical, and have a plan shape as follows: From corner 30 to corner 41, thence along an (optional) right-corner cut-off line to 42, thence along backline 34 to corner 43, then along (optional) left-corner cutoff to 44, thence to corher 38. From corner 38 the frontline continues along the inner face of flange 28B to corner 45 and then along the inset line to 46, thence forwardly at a slight slant to 47 where line 4647 blends into the circular arc 47- }48 -49, then again at a slight slant rearwardly from 49 to 50, along inset line 50-51 and then along the inner face of flange 28B to corner 30. Each plate has a slot 52 along centerline (55 of Figure 4). This slot receives the ends of pins extending through a cam plate, as will later be shown and keeps the cam plate going straight. In addition, top and bottom plates A and E have holes of appropriate size and aligned with pivots 25R and 25L to receive the reduced diameter ends of such pivots. Also, the tongues AT (of top plate A) and ET of bottom plate E each have a central aperture 22A which serves to receive the stub-type top and bottom pivot end-shafts 22 of the hub 21 of the handle 2123--24.

The front vertically extending flange 28B of the mounting plate 28 has a rectangular slot 28C in it which is of a width (as viewed in Figures 4 and 8) to receive the forwardly extending tongues AT and ET of the plates A and E, these tongues being the portions from corner 46 to 47, around arc 47-4849 and thence from 49 to corner 50. The vertical height of the slot 28C in flange 28B is from the upper surface of horizontal portion 28A to the upper surface of plate A (see Figure 5). When assembled plates A and E (with all mechanisms between them) are simply pushed forward to extend the tongues AT and ET through the slot 28C in flange 28B until screws 40R and 40L can be placed. This holds the assembly firmly together.

Now it will be noted that hub 21 has a large diameter central portion 21B which (for good looks) has the same diameter as arc 47-48-49 and concentric top and bottom smaller diameter end shafts 2222. A lever arm 23 extends from one side and has a shaped handhold 24 at the end. The axial length of the portion 21B is from the upper surface of bottom plate E to the under surface of top plate A and this hub portion 21B therefore serves to space apart vertically the front '(tongue) ends of plates A and E. At the same time The central portion 21B of the hub has a slot 21C which (from the standpoint of vertical elevation) 00- cupies the middle tier portion C, and as shown in Figures 4 and 8 the slot 21C extends more than half-way through the hub 21B. The exact boundary of this slot 21C as shown in Figure 8, is along straight line 55-56. thence along the circumferential arc (of hub 21B) 56S7--47--48--55. The diameter of this arc is the same as are 47-48-49. Lever arm 23 may, if desired, be slanted up a little, as shown in Figure l, but this is optional.

It is entirely possible to machine hub 21, pivots 22, lever arm 23 and hand-hold 24 from steel or other materials andassemble after the manner shown in application Serial No. $20,555 but this unit can be made most economically in large numbers by die-casting in permanent molds and such method of manufacture is preferred.

The spacing provided by the axial dimension of hub portion 21B and by the central portions of pivots 25R and 25L, together with the retention provided by frame 28, flange 28B and screws 40R and 40L therefore provides spaced parallel top and bottom plates A and E respectively, between which the remainderof mechanism is situated and operates. Thus extending back from hub portion 21B and in the middle tier C is a link 58 which is pivoted to the hub 21B by, a pressed-in pivot pin 59 and is coupled at its forward end by a pressed-in pivot pin 60 to upper and lower identical cam plates 62 and 64. The cam plates occupy the top and bottom tiers B and D respectively and are held together, but in spaced relation at the front edge by the rear end of link 58 (which occupies the middle tier between them), and at their rear edge by the pin 61 which has a larger diameter central portion 61A which serves as a stop to hold cam plate 62 and 64 spaced. The upper and lower ends of pins 60 and 61 reach into. and slide in slots 52 of the top and bottom plates A and E and hence the cam plates 62 and 64 can slide back and forth but cannot rotate appreciably, being thus held by the ends of pins 60-61. Each cam plate has a sideward extending slot as at 62A and 62B the slots being tipped at 62C and 62D respectively. Accordingly as the handle 23-24 is moved in the direction to 'OPEN (see arrow, Figure 4) the cam plates will be translated rearwardly from the Window-Closed position of Figure 4, towards the Window Open position of Figure 8). The movement for closing is reversed to CLOSE (see arrow, Figure 8). The movement may be halted at any intermediate position and the mechanism will stay due to inherent friction of the parts (particularly due to friction between the armsliders and the window frame tubes as will be described). The movement of earns 62 and 64 (which act as a symmetrical upper and lower pair) is communicated to the arms 26R and 26L as follows:

On pivots 25R and 25L there are, in each instance a three layer stack forming the operator-end of the arms 26R and 26L respectively. As these are similar (right and left) only one need be described. There is first a slightly angularly shaped bell-crank arm 68 which occupies the middle tier. This arm has a central pivot hole which pivots on pin 25R. The inner end of crank 68 carries a pin 69 which extends upward through the top tier Band terminates just short of the lower surface of top plate A. On this upper end of pivot 69 is a roller 70 which occupies one of the slots, in cam plate 62. The same pin 69 also extends down through the Bottom tier D. and stops just short of the upper surface of Bottom plate E and on this lower end is another roller 70 which occupies the corresponding slot in the lower cam. plate 64. Hence as. the cam plates are translated back and forth; they.- move rollers 70-70 (upper and lower) and this swings lever 68 around pivot 25R. Lever 68 extends forwardly and is curved olf at end 71. The lever 26K is situated in; the Top tier B and its inner end is notched at 75 to fit pivot pin 25R. A short spacetaker and stiffener plate 74 is located in the Bottom tier D and also extends to curve 71. The three pieces 26R, 68 and, 74 are riveted solidly together at- 72 and 73. If desired, 74' can be extended out on lever- 26R to-addstrength.

The arm 26L is similar. Hence as the handle 23-24 is swung back and forth between the Figure 4 (window closed) position and-Figure 8 (window open) position the l lfllf lfili and 2. ..LW 1l be... correspondingly. moved 6" to the positions as shown in these figures. Figure 3 also shows the opening and closing directions of movement.

The connection between the arms 26R and 26L and the lower element of the window sash 10. are by independent sliders, one for each arm. Various forms of sliders are shown in the art but I prefer the novel construction shown herein, which is a feature of this invention. This construction is best shown in Figures 1, 2, 3, 4, 6 and 7. Thus along the lower element of the sash 10 there are placed two thin-wall tubes 78R and 78L each has a slot 79 extending from end to end, the slot being of a width and oriented slightly upward from center, as shown in Figure 6, to accommodate slight variations in the entering direction of the arms 26R and 26L as the window is opened. The tubes 78R and 78L are held in place by wood screws 80 which can be placed through the slot 79 as shown in Figure 6. The tubes extend outwardly (left and right) beyond the ends of arms 26R and 26L when the latter are in the Window Closed position shown in dotted lines in Figure 3, and at the middle of the window sash the tubes extend inwardly slightly beyond the position the arms 26R and 26L stop when in the normal Window Open" position, shown in full lines inFigure 3. The tubes 78R: and 78L accordingly are spaced by distance S, see Figure 1.

Upon the end of each arm 26R and 26L there is a cylindrical plug 81-81 which is slotted part way through to receive the end of the arm, the plugs being held in place by pivot pins 82-82. The plugs are preferably made of plastic (nylon is excellent) and are sized so as neatly to slide on the insides of the slotted tubes 78R and 78L. The sliding action provides enough static friction so as to hold the arms in place at any intermediate condition of window opening desired when the handle may be left out since the motion multiplication between movement of theslides and the crank hub 21B is very large, even slight friction in the operator mechanism is enough to hold the mechanism without added detents, even tho the plugs 81-81 should slide slightly in the tubes 78R and 78L, as during gusty weather. When the window moves toward open position the arms 26R and 26L are slightly flexed upwardly (see Figure 2). This increases the sliding and working friction since pressure is thereby increased between the plugs. 81 and tubes 78R and L. This therefore increases friction toward the open position.

When the window is in the open position (full lines, Figure 3), the arms 26R and L can be flexed slightly to the position shown in dot-dash lines, thereby to release the plugs 81-81 into the space S between the ends of tubes 78R and 78L. This frees the sash S to permit further movement beyond the open position to the Servicing position, shown in dotted lines in Figure 2.

. In this position the window may be cleaned and storm sash applied and removed.

that the flyscreen is mounted frame as shown in Figure 2.

When the window operator is moved from open to close It is noted parenthetically on the inside of the window position and vice versa the link 58 not only draws back and forth but also has a sidewise component of motion, particularly at its rear end. The slight space between the inner face of flange 28B and the line of corners 46- 50 (see Figure 8) permits the insertion of a vertical insect shield 85 which is a thin plate slotted to permit link 58 to pass through. The plate works sideways to accommodate movement of link 58 as it is moved and closes ofi access through slot 280 thus preventing insect entrance at the plane of the fly screen (see Figure 2).

When the window operator is moved to the open or closed position the final movement of pin 59 on link 58 is very powerful. In moving to the full open position this opening motion force, which is imposed on levers 26R and 26L is not topposed. and these levers simply moved steadily and powerfully to thepositionofFigures 7. 3 and 8. However when the motion is toward closing position the window sash 'finally closes on the frame 11 and the tubes 78L and 78R are then in the positions shown in dotted lines in Figure 3 and in full lines in Figure 4. The sliders 81 are of course in the tubes and are then held from moving inwardly but the kinematic relationship of the operator parts is such that the motions of the operator are not completed until the arms 26R and 26L are brought home to the Figure 4 position. This imposes a strong window closing force on the arms 26R and 26L which is even suflicient to fiex them edgewise as illustrated (dotted lines, Figure 3). Such strong force is desirable as many windows work stiff, especially in overcoming the resiliency of weather-stripping materials. It is noted that the closing force on the sash 10 is near the corners. This is desirable, in that it prevents bowing the lower element of the sash.

In Figures 10-13 there is illustrated a slightly modified form of the invention adapted to the operation of casement windows. The two kinds of casement windows are shown and the modified operator works satisfactorily for each. In Figure 11 there is illustrated a well-known steel or aluminum sash casement. In Figure 10 there is illustrated the newer sliding-pivot casement, which is simply a canopy-type window (Figures 1-3) turned on its side. Both windows (Figures 10 and 11) are of the "hinges-on-the-right variety. The operator illustrated will work just as well for the hinges-on-the-left variety by merely re-assembling it by turning the handle (21- 23-24) and the plates assembly (A-D) over.

The operator mechanism generally designated 100 is composed of basically the same parts as the operator mechanism 20, but with slight changes. Thus the frame plate 28, top plate A, bottom plate E, insect shield 85, handle unit (21, 23, 24) pin 59 can be identical with those shown in Figures 1-9 except that the slot 52 is omitted from plates A and E and one pivot hole (as for pivot 25L) is moved toward the center line of the plates. The arm assembly 126 is slightly modified and utilizes top and bottom crank plates 127 and 133 which are riveted at 129129 to the main arm 126. The pivot 125 is preferably relocated nearer the centerline of plates A and E, and the main arm 126 terminates at 130 with a semicircular notch 131 fitted to the enlarged central portion of pivot 125. Pivot 125 has reduced diameter ends which fit into holes in plates A and E and pivot 125 is tubular so as to permit the machine screw 132 to'pass therethru and thread into the mounting plate 28. The location of the other fastening screw 134 remains unchanged and it passes thrua tubular member like 125 which however, merely acts as a spacer and not as a pivot.

The bellcrank levers 127133 occupy the top tier space D and Bottom tier space B and their short ends (right ends in Figures 12 and 13) are spaced apart by the thickness of the Middle Tier C. These bellcranks carry a pivot pin 136 which reaches thru from the under side of theTop Plate A to the upper side of the Bottom Plate E and pivoted on this pin and located in the Middle Tier C is a link 138, somewhat longer than corresponding link 58 in the Figures 1-9, which extends back to pivot pin 159 on hub 21. The hub 21 pivots on its two upper and lower stub shafts 122 and as the hub is turned the link 138 is pushed or pulled, thereby swinging the bellcrank levers assembly 127-133 and hence the arm 126 about the pivot 125.

. When the operator 100 is in the position shown in full lines in Figure 10 the arm 126 is straight out i.e. normal to the plane of the closed window, and the operator 100 is installed on the window sill so that arm 126 is then aligned parallel and in line with the slotted tube 178 attached to the window sash S. When the operator 100 is moved to the dotted line position of Figure 10 or 11, the window is clos'ed'and' the arm 126 flexed in bringing the window home to closed position.

. It is noted in respect to Figures 10 and 11, that in the Open"portion access is provided for servicing the window. The operator mechanisms 20 (of Figures 1-9), (of Figures 10-13) are preferably designed so that the pins 59 (of Figures 1-9) and 159 (of Figures l0l3) will move slightly over center at the closed window position.

As many variations in mode of construction of the apparatus herein illustrated and described will suggest themselves to those skilled in the art, the invention is not limited except as defined in the appended claims.

What I claim is:

1. A closure operator comprising a subframe having a base portion adapted to be fastened to a closure surround and having an upstanding flange thereon provided with an aperture therein from the base portion upwardly, a pair of frame plates each having a corresponding apertured tongue extending at one edge and along the centerline' thereof, said tongues of said plates being extended thru the aperture of said flange and received neatly thereby when the plates are maintained in vertically spaced parallel relation, a pair of pivot tubes each having an enlarged central portion of equal axial length and reduced end diameters, said frame plates being apertured at each side of the centerlines thereof and spaced from said tongues, the reduced ends of said tubes being received in said apertures and the plates held in parallel spaced relation by said enlarged central portions, fasteners'extending thru the plates and tubes and into the base portion of said subframe for holding the parts assembled, a hub having an operating handle extending generally radially therefrom located between the tongues of said plates and pivoted thereon at said apertures, at least one closure operating arm pivotally mounted on one of the pivot tubes and having a short end extending between said plates and a long end extending outwardly beyond said plates and provided at its long end with means for engaging a closure for operating the closure, a hub pivotally mounted between said plates, and means connecting the short end of said arm with said hub for arcuately swinging the arm as the hub is rotated.

. 2. The apparatus of claim 1 further characterized in that an arm is provided for each pivot tube, and said means connecting the short end of said arm includes a cam mounted for translatory movement, said cam having a pair of elongated slots therein, the longitudinal axis of said slots being generally perpendicular to the line of movement of said cam and cam followers mounted for movement in said cam slots to operatively cause the arms to rotate as the cam is translated.

3. The apparatus of claim 1 further characterized in that'said means connecting the short end of said arm includes cam means mounted between the plates for translatory movement.

4. The apparatus of claim 1 further characterized in that'said plates are symmetrical and that there is provided means for removably securing the plates, pivot tubes, arms, and hub handle unit together in an assembled relation on the sub-frame, said arms extending outwardly from said plates on the opposite Side of the plates from the hub handle unit, said plates, pivot, tube arms, and hub handle unit constructed to be removed from the sub-frame and turned over to accommodate right or left installation.

References Cited in the file of this patent UNITED STATES PATENTS 1,198,144 ORourke Sept. 12, 1916 2,013,608 Jacobs Sept. 3, 1935 2,022,036 Haberstump Nov. 26, 1935 2,775,446 Stavenau Dec. 25, 1956 FOREIGN PATENTS 85,521 Switzerland June 16, 1920 

